It is becoming commonplace to equip automotive vehicles with supplemental inflatable restraint (SIR) systems which sense a crash of significant severity and deploy air bags for the protection of vehicle occupants. Since such a crash may be very severe occupants may need emergency assistance and yet be unable to summon help. It is therefore proposed to automatically send an emergency signal whenever an air bag is deployed. Remote stations receiving such a signal will then be able to dispatch emergency services. A variety of communication systems are available for use in a vehicle and could be utilized for an emergency signal. The issue then is how to detect an air bag deployment for the purpose of activating a communication device.
It has been proposed to detect deployment by monitoring messages from the SIR system on the vehicle bus. A disadvantage of this approach is that the bus is likely to fail during a crash. Such buses are not designed for this purpose. Further the cost to power the SIR controller for bus activity would by prohibitive. A long term solution is to add a wire to couple the SIR to a communication device. This solution is not readily applicable to current vehicles or those which have been designed and qualified for SIR operation since such a system change would likely require the significant step of repeating a crash series for revalidation.
To avoid such concerns, it is desirable to detect air bag deployment independently of the SIR system. It is also desirable that detection arrangement be applicable to all types and makes of SIR systems. Then the detection and signaling apparatus could be produced as an aftermarket item for installation in existing vehicles. It is also desirable that such an apparatus be simple and inexpensive.